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Protoporphyria, Erythropoietic - Top 30 Publications


Clinical, Biochemical, and Genetic Characterization of North American Patients With Erythropoietic Protoporphyria and X-linked Protoporphyria.

Autosomal recessive erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare photodermatoses presenting with variable degrees of painful phototoxicity that markedly affects quality of life. The clinical variability, determinants of severity, and genotype/phenotype correlations of these diseases are not well characterized.

Disturbed iron metabolism in erythropoietic protoporphyria and association of GDF15 and gender with disease severity.

Patients with erythropoietic protoporphyria (EPP) have reduced activity of the enzyme ferrochelatase that catalyzes the insertion of iron into protoporphyrin IX (PPIX) to form heme. As the result of ferrochelatase deficiency, PPIX accumulates and causes severe photosensitivity. Among different patients, the concentration of PPIX varies considerably. In addition to photosensitivity, patients frequently exhibit low serum iron and a microcytic hypochromic anemia. The aims of this study were to (1) search for factors related to PPIX concentration in EPP, and (2) characterize anemia in EPP, i.e., whether it is the result of an absolute iron deficiency or the anemia of chronic disease (ACD). Blood samples from 67 EPP patients (51 Italian and 16 Swiss) and 21 healthy volunteers were analyzed. EPP patients had lower ferritin (p = 0.021) and hepcidin (p = 0.031) concentrations and higher zinc-protoporphyrin (p < 0.0001) and soluble-transferrin-receptor (p = 0.0007) concentrations compared with controls. This indicated that anemia in EPP resulted from an absolute iron deficiency. Among EPP patients, PPIX concentrations correlated with both growth differentiation factor (GDF) 15 (p = 0.012) and male gender (p = 0.015). Among a subgroup of patients who were iron replete, hemoglobin levels were normal, which suggested that iron but not ferrochelatase is the limiting factor in heme synthesis of individuals with EPP.

Ferrochelatase gene mutation in Singapore and a novel frame-shift mutation in an Asian boy with erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) is a rare inherited disorder of heme biosynthesis caused by decreased activity of the enzyme ferrochelatase (FECH ). The frequency of the hypomorphic c.333-48C allele in a population directly contributes to the prevalence of EPP in the same population. This study sought to identify the molecular basis of EPP in a Chinese patient from Singapore and the c.333-48C allele frequency among the Chinese population in Singapore.

A promising new strategy for monitoring erythropoietic protoporphyria therapy.

Protoporphyrin IX in the skin measured noninvasively predicts photosensitivity in patients with erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) is a rare genetic disease that causes severe sensitivity to visible light as a result of protoporphyrin IX (PpIX) accumulation in the skin.

Identification of FECH gene multiple variations in two Chinese patients with erythropoietic protoporphyria and a review.

Erythropoietic protoporphyria (EPP), an autosomal dominant disease, is caused by partial deficiency of ferrochelatase (FECH), which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630-634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene (c.973 delA) in one proband (patient A) and a pathogenic FECH mutation (c.1232 G>T) in the other (patient B) and also observed some nucleotide variations (c.798 C>G, c.921 A>G, IVS1-23 C>T, IVS3+23 A>G, IVS9+35 C>T, and IVS3-48 T>C) in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient's relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.

Novel Treatment Using Cimetidine for Erythropoietic Protoporphyria in Children.

Erythropoietic protoporphyria (EPP) is a rare hereditary disease of heme biosynthesis that manifests as severe photosensitivity and hepatotoxicity. There have been no effective treatments to date. Cimetidine has been shown to inhibit heme biosynthesis and results in symptomatic improvement in patients with acute intermittent porphyria (AIP) and porphyria cutanea tarda (PCT). There is only 1 report in the literature describing the use of cimetidine in the effective treatment of an adult patient with EPP.

Cutaneous changes in long-standing erythropoietic protoporphyria.

Erythropoietic protoporphyria results in highly increased photosensitivity of the skin. Solar irradiation causes sunburn-like symptoms with erythema, edema and wheals. We report the case of a 60-year-old man suffering from erythropoietic protoporphyria since his childhood who additionally developed chronic cutaneous lichenoid papules in sun-exposed skin areas. Vaporization with both electrocautery and carbon dioxide laser proved to be a successful treatment option.

Influence of meteorological data on sun tolerance in patients with erythropoietic protoporphyria in France.

Erythropoietic protoporphyria (EPP) is a rare metabolic disorder, characterized by photosensitivity, caused by errors of the haem biosynthetic pathway. Avoidance of sun exposure is recommended; however, some patients suggested a paradoxical improvement of symptoms when they move to sunny areas.

Afamelanotide: A Review in Erythropoietic Protoporphyria.

Afamelanotide (SCENESSE(®)) is a synthetic α-melanocyte stimulating hormone analogue and first-in-class melanocortin-1 receptor agonist that is approved in the EU for the prevention of phototoxicity in adults with erythropoietic protoporphyria (EPP). It is administered subcutaneously as a biodegradable, controlled-release implant containing 16 mg of afamelanotide. This article reviews the clinical efficacy and tolerability of afamelanotide in EPP and summarizes its pharmacological properties. In the phase III trial, CUV039, afamelanotide treatment improved light tolerance in patients with EPP. Compared with placebo, afamelanotide treatment enabled patients to spend more time in direct sunlight without pain and increased the time to the appearance of the first symptoms of phototoxicity provoked by a standardized light source. Afamelanotide was generally well tolerated in this trial, with no drug-related serious adverse events reported. Commonly occurring adverse reactions included headache and implant-site reactions. Efficacy and safety data from earlier phase III trials are consistent with those from the CUV039 trial. Afamelanotide, approved in the EU for the prevention of EPP phototoxicity, represents a useful addition to the management of the disorder.

A precursor-inducible zebrafish model of acute protoporphyria with hepatic protein aggregation and multiorganelle stress.

Protoporphyria is a metabolic disease that causes excess production of protoporphyrin IX (PP-IX), the final biosynthetic precursor to heme. Hepatic PP-IX accumulation may lead to end-stage liver disease. We tested the hypothesis that systemic administration of porphyrin precursors to zebrafish larvae results in protoporphyrin accumulation and a reproducible nongenetic porphyria model. Retro-orbital infusion of PP-IX or the iron chelator deferoxamine mesylate (DFO), with the first committed heme precursor α-aminolevulinic acid (ALA), generates high levels of PP-IX in zebrafish larvae. Exogenously infused or endogenously produced PP-IX accumulates preferentially in the liver of zebrafish larvae and peaks 1 to 3 d after infusion. Similar to patients with protoporphyria, PP-IX is excreted through the biliary system. Porphyrin accumulation in zebrafish liver causes multiorganelle protein aggregation as determined by mass spectrometry and immunoblotting. Endoplasmic reticulum stress and induction of autophagy were noted in zebrafish larvae and corroborated in 2 mouse models of protoporphyria. Furthermore, electron microscopy of zebrafish livers from larvae administered ALA + DFO showed hepatocyte autophagosomes, nuclear membrane ruffling, and porphyrin-containing vacuoles with endoplasmic reticulum distortion. In conclusion, systemic administration of the heme precursors PP-IX or ALA + DFO into zebrafish larvae provides a new model of acute protoporphyria with consequent hepatocyte protein aggregation and proteotoxic multiorganelle alterations and stress.-Elenbaas, J. S., Maitra, D., Liu, Y., Lentz, S. I., Nelson, B., Hoenerhoff, M. J., Shavit, J. A., Omary, M. B. A precursor-inducible zebrafish model of acute protoporphyria with hepatic protein aggregation and multiorganelle stress.

A Novel Mutation in the FECH Gene in a Czech Family with Erythropoietic Protoporphyria and a Population Study of IVS3-48C Variant Contributing to the Disease.

Erythropoietic protoporphyria (EPP), a chronic erythropoietic porphyria, is characterized by excess accumulation of protoporphyrin, particularly in erythroid cells. EPP inheritance is complex, almost always associated with two molecular defects. In most EPP patients, clinical expression requires coinheritance of a private ferrochelatase (FECH) mutation trans- to a hypomorphic FECH*IVS3-48C allele. This leads to a decrease of FECH activity below the critical threshold. This is characterized by cutaneous photosensitivity in early childhood such as itching, burning, swelling and redness in sun-exposed areas. Hepatic failure occurs in some patients (about 1-10 % of EPP patients), which may necessitate liver transplantation. We investigated a Czech family with two patients with manifested EPP in four generations. We found a novel mutation, c.84G >A, in the FECH gene in four individuals including proband and his mother (G84A transition in exon 2; p.W28*). Both clinically manifested probands inherited the hypomorphic IVS3-48C allele as well, while two clinically latent individuals with FECH mutation did not. To address the question whether the relatively low incidence of EPP in the Czech Republic might be due to lower frequency of the IVS3-48C allele, we screened for the frequency of the low expression allele in a control Czech (West Slaves) Caucasian population. Such study has not been performed in any Slavic population. Among 312 control individuals, there were no IVS3-48C/C (c.68-23C-T) homozygotes; 35 IVS3-48C/T heterozygous individuals were detected. The frequency of IVS3-48C allele was thus found to be 5.5 % in the Czech population, comparable to most West Caucasian populations.

Pitfalls in Erythrocyte Protoporphyrin Measurement for Diagnosis and Monitoring of Protoporphyrias.

Laboratory diagnosis of erythropoietic protoporphyria (EPP) requires a marked increase in total erythrocyte protoporphyrin (300-5000 μg/dL erythrocytes, reference interval <80 μg/dL) and a predominance (85%-100%) of metal-free protoporphyrin [normal, mostly zinc protoporphyrin (reference intervals for the zinc protoporphyrin proportion have not been established)]; plasma porphyrins are not always increased. X-linked protoporphyria (XLP) causes a similar increase in total erythrocyte protoporphyrin with a lower fraction of metal-free protoporphyrin (50%-85% of the total).

X-linked dominant protoporphyria: The first reported Japanese case.

A 12-year-old boy with photosensitivity since 3 years of age presented with small concavities on both cheeks, the nasal root and the dorsal surface of both hands. According to the clinical features, erythropoietic protoporphyria (EPP) was suspected. Urine and blood samples were tested for porphyrin derivatives, which revealed a markedly elevated level of erythrocyte protoporphyrin (EP) and a diagnosis of EPP was made. The patient's mother had no photosensitivity, however, lesions appearing slightly as small scars were found on the dorsum of her right hand; his elder sister and father showed no rash. The EP levels were elevated in samples from his mother and mildly elevated in those from his elder sister and father. To obtain a definitive diagnosis, genetic analyses were performed using samples from all family members, which revealed no mutations in the ferrochelatase-encoding gene (FECH), which is responsible for EPP. Instead, a pathological mutation of the 5-aminolevulinic acid synthase-encoding gene (ALAS2) was identified in samples from the patient, his mother and his elder sister, confirming a definitive diagnosis of X-linked dominant protoporphyria (XLDPP). This is the first Japanese family reported to have XLDPP, demonstrating evidence of the condition in Japan. In addition, because XLDPP is very similar to EPP in its clinical aspects and laboratory findings, a genetic analysis is required for the differential diagnosis.

Human Erythroid 5-Aminolevulinate Synthase Mutations Associated with X-Linked Protoporphyria Disrupt the Conformational Equilibrium and Enhance Product Release.

Regulation of 5-aminolevulinate synthase (ALAS) is at the origin of balanced heme production in mammals. Mutations in the C-terminal region of human erythroid-specific ALAS (hALAS2) are associated with X-linked protoporphyria (XLPP), a disease characterized by extreme photosensitivity, with elevated blood concentrations of free protoporphyrin IX and zinc protoporphyrin. To investigate the molecular basis for this disease, recombinant hALAS2 and variants of the enzyme harboring the gain-of-function XLPP mutations were constructed, purified, and analyzed kinetically, spectroscopically, and thermodynamically. Enhanced activities of the XLPP variants resulted from increases in the rate at which the product 5-aminolevulinate (ALA) was released from the enzyme. Circular dichroism spectroscopy revealed that the XLPP mutations altered the microenvironment of the pyridoxal 5'-phosphate cofactor, which underwent further and specific alterations upon succinyl-CoA binding. Transient kinetic analyses of the variant-catalyzed reactions and protein fluorescence quenching upon binding of ALA to the XLPP variants demonstrated that the protein conformational transition step associated with product release was predominantly affected. Of relevance is the fact that XLPP could also be modeled in cell culture. We propose that (1) the XLPP mutations destabilize the succinyl-CoA-induced hALAS2 closed conformation and thus accelerate ALA release, (2) the extended C-terminus of wild-type mammalian ALAS2 provides a regulatory role that allows for allosteric modulation of activity, thereby controlling the rate of erythroid heme biosynthesis, and (3) this control is disrupted in XLPP, resulting in porphyrin accumulation.

Incomplete erythropoietic protoporphyria caused by a splice site modulator homozygous IVS3-48C polymorphism in the ferrochelatase gene.

Erythropoietic protoporphyria (EPP) is an inherited cutaneous porphyria caused by both the partial deficiency of ferrochelatase (FECH) and the existence of cytosine at IVS3-48 in trans to a mutated FECH allele. However, physicians occasionally encounter patients with EPP with a mild phenotype associated with a slight increase in the erythrocyte-free protoporphyrin concentration and no FECH gene mutations. In this study, genetic analyses were performed on three patients with a mild phenotype of EPP, with photosensitivity, slightly increased erythrocyte-free protoporphyrin concentrations and only a few fluorocytes in the peripheral blood. After obtaining the patients' and their parents' informed consent, a direct sequence analysis of the FECH gene and a restriction fragment length polymorphism analysis were performed on samples from the patients. The FECH gene mutation was not detected in the direct sequence analyses in any of the patients. However, all three patients had the homozygous IVS3-48C polymorphism. These findings suggest that homozygous IVS3-48C polymorphism of the FECH gene is associated with a slight elevation of the protoporphyrin level in erythrocytes, resulting in a mild EPP phenotype.

A patient diagnosed herself with erythropoietic protoporphyria after googling photosensitivity.

Erythropoietic protoporphyria (EPP) is rare genetic disease caused by decreased activity of the eighth enzyme in the haem synthesis. Patients are photosensitive, getting stinging and burning sensations in the skin after sun exposure. Delayed diagnosis of these patients is not seldom because of the rarity in combination with not always visible skin symptoms. This is a case report of a 43-year-old woman who diagnosed herself with EPP after googling photosensitivity. Genetic testing revealed a formerly undescribed mutation, c. 1096-3C>G in combination with the polymorphism, c.333-48T>C.

Homeostasis of iron and hepcidin in erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are genetic abnormalities of heme synthesis that result in excess production of protoporphyrin and that manifest as severe photosensitivity. These disorders are often associated with iron deficiency anaemia (IDA). Our aim was to determine whether hepcidin is increased in EPP/XLP patients, resulting in decreased enteral iron absorption and IDA.

A second attack of cholestasis associated with erythropoietic protoporphyria was successfully treated by plasma exchange and blood transfusion.

Erythropoietic protoporphyria (EPP) is a rare hereditary disease that can sometimes cause acute liver failure based on cholestasis. Acute liver failure is a fatal complication and is associated with EPP in 1-4 % of patients. Although it is extremely difficult to recover from acute liver failure, we experienced an important case of EPP where the patient recovered from the first attack of cholestasis with antibiotic treatment. The patient recovered from a second attack of cholestasis with blood infusion and plasma transfusion. This case suggests that the supply of heme by blood transfusion and the elimination of excess protoporphyrin production by plasma exchange may be a useful treatment for patients with acute cholestasis associated with EPP.

Reply to: "Impaired expression of multidrug resistance-associated protein 2 and liver damage in erythropoietic protoporphyria".

Afamelanotide for Erythropoietic Protoporphyria.

Erythropoietic protoporphyria is a severe photodermatosis that is associated with acute phototoxicity. Patients with this condition have excruciating pain and a markedly reduced quality of life. We evaluated the safety and efficacy of an α-melanocyte-stimulating hormone analogue, afamelanotide, to decrease pain and improve quality of life.

Treatment for erythropoietic protoporphyria.

Experimental protoporphyria: effect of bile acids on liver damage induced by griseofulvin.

The effect of bile acids administration to an experimental mice model of Protoporphyria produced by griseofulvin (Gris) was investigated. The aim was to assess whether porphyrin excretion could be accelerated by bile acids treatment in an attempt to diminish liver damage induced by Gris. Liver damage markers, heme metabolism, and oxidative stress parameters were analyzed in mice treated with Gris and deoxycholic (DXA), dehydrocholic (DHA), chenodeoxycholic, or ursodeoxycholic (URSO). The administration of Gris alone increased the activities of glutathione reductase (GRed), superoxide dismutase (SOD), alkaline phosphatase (AP), gamma glutamyl transpeptidase (GGT), and glutathione-S-transferase (GST), as well as total porphyrins, glutathione (GSH), and cytochrome P450 (CYP) levels in liver. Among the bile acids studied, DXA and DHA increased PROTO IX excretion, DXA also abolished the action of Gris, reducing lipid peroxidation and hepatic GSH and CYP levels, and the activities of GGT, AP, SOD, and GST returned to control values. However, porphyrin accumulation was not prevented by URSO; instead this bile acid reduced ALA-S and the antioxidant defense enzymes system activities. In conclusion, we postulate that DXA acid would be more effective to prevent liver damage induced by Gris.

Impaired expression of ATP-binding cassette transporter G2 and liver damage in erythropoietic protoporphyria.

Bone marrow transplant for X-linked protoporphyria with severe hepatic fibrosis.

XLP is an erythroid porphyria that results in variable cutaneous photosensitivity due to accumulation of protoporphyrin. The genetic defect in XLP is mutation of the gene ALAS2, resulting in gain of function for the erythroid enzyme 5-aminolevulinate synthase 2. Previous reports have shown that protoporphyrin-induced liver disease may also occur in XLP, occasionally severe enough to warrant liver transplantation; however, transplantation may be followed by injury to the graft due to continued presence of the underlying metabolic disorder in the bone marrow. We present a case of XLP with severe liver disease successfully treated with HPCT to avoid liver transplantation. The case also demonstrates the feasibility of reduced intensity transplant to provide engraftment sufficient for correction of porphyria and tolerability of reduced intensity conditioning containing TLI in the face of severe liver injury.

An α-MSH analog in erythropoietic protoporphyria.

X-chromosomal inactivation directly influences the phenotypic manifestation of X-linked protoporphyria.

X-linked protoporphyria (XLP), a rare erythropoietic porphyria, results from terminal exon gain-of-function mutations in the ALAS2 gene causing increased ALAS2 activity and markedly increased erythrocyte protoporphyrin levels. Patients present with severe cutaneous photosensitivity and may develop liver dysfunction. XLP was originally reported as X-linked dominant with 100% penetrance in males and females. We characterized 11 heterozygous females from six unrelated XLP families and show markedly varying phenotypic and biochemical heterogeneity, reflecting the degree of X-chromosomal inactivation of the mutant gene. ALAS2 sequencing identified the specific mutation and confirmed heterozygosity among the females. Clinical history, plasma and erythrocyte protoporphyrin levels were determined. Methylation assays of the androgen receptor and zinc-finger MYM type 3 short tandem repeat polymorphisms estimated each heterozygotes X-chromosomal inactivation pattern. Heterozygotes with equal or increased skewing, favoring expression of the wild-type allele had no clinical symptoms and only slightly increased erythrocyte protoporphyrin concentrations and/or frequency of protoporphyrin-containing peripheral blood fluorocytes. When the wild-type allele was preferentially inactivated, heterozygous females manifested the disease phenotype and had both higher erythrocyte protoporphyrin levels and circulating fluorocytes. These findings confirm that the previous dominant classification of XLP is inappropriate and genetically misleading, as the disorder is more appropriately designated XLP.

Extreme photosensitivity in a patient with erythropoietic protoporphyria.

X-linked dominant protoporphyria: response to "Cutaneous porphyrias part 1".